Standard Article

You have free access to this content

Methane reforming kinetics, carbon deposition, and redox durability of Ni/8 yttria-stabilized zirconia (YSZ) anodes

Advances in Electrocatalysis, Materials, Diagnostics and Durability

Performance degradation

High-temperature fuel cells

  1. E. Ivers-Tiffée1,
  2. H. Timmermann1,
  3. A. Leonide1,
  4. N. H. Menzler2,
  5. J. Malzbender2

Published Online: 15 DEC 2010

DOI: 10.1002/9780470974001.f500063

Handbook of Fuel Cells

Handbook of Fuel Cells

How to Cite

Ivers-Tiffée, E., Timmermann, H., Leonide, A., Menzler, N. H. and Malzbender, J. 2010. Methane reforming kinetics, carbon deposition, and redox durability of Ni/8 yttria-stabilized zirconia (YSZ) anodes. Handbook of Fuel Cells. .

Author Information

  1. 1

    Universität Karlsruhe (TH), Karlsruhe, Germany

  2. 2

    Institute of Energy Research, IEF, Jülich, Germany

Publication History

  1. Published Online: 15 DEC 2010

Abstract

Anodes for stationary SOFC systems are most likely to be operated with natural gas at temperatures above 800 °C, whereas mobile SOFC applications such as APUs (auxiliary power units) operated below 800 °C use (liquid) hydrocarbons. The fuel (gasoline or diesel) cannot be converted by 100% in the reformer and so a reformate containing higher hydrocarbons has to be converted at the anode. In operation with hydrocarbons, at high fuel utilization or at sequential redox cycles, the nickel catalyst is subject to various degradation processes. The dominating process depends on the anodic oxygen partial pressure applied and possibly deteriorates the electrochemical performance of the anode.

Sequential cyclic reduction and oxidation (redox) can quickly lead to an aging of the anode or even a complete failure of the cell (fracture of the thin film electrolyte). In operation with hydrocarbons, i.e., at low oxygen partial pressures, degradation ranging from (i) reversible damage by occupancy of the Ni catalyst surface with various deposits to (ii) irreversible damage to the Ni catalyst by carbon whisker growth occurs.

Moreover, the kinetics of methane conversion under various operating conditions, the carbon formation in the presence of higher hydrocarbons (acetylene), and the analysis of electro-oxidation and gas diffusion in stable operation with hydrogen or biomass-derived gas are also treated in this article.

Keywords:

  • Ni/8 YSZ anode;
  • methane reforming kinetics;
  • redox durability;
  • hydrocarbons;
  • carbon deposition;
  • biogas;
  • impedance analysis;
  • distribution of relaxation times